CVE-2026-40891 json
OpenTelemetry dotnet: Unbounded `grpc-status-details-bin` parsing in OTLP/gRPC retry handling
published 2026-04-23 6 mo ago modified 2026-10-26 13 d ago also EUVD-2026-25268 , GHSA-mr8r-92fq-pj8p
- cvss
- 5.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 8%
- public exploits
- 0
- none known
Summary
OpenTelemetry dotnet is a dotnet telemetry framework. From 1.13.1 to before 1.15.2, When exporting telemetry over gRPC using the OpenTelemetry Protocol (OTLP), the exporter may parse a server-provided grpc-status-details-bin trailer during retry handling. Prior to the fix, a malformed trailer could encode an extremely large length-delimited protobuf field which was used directly for allocation, allowing excessive memory allocation and potential denial of service (DoS). This vulnerability is fixed in 1.15.2.
Patch / fix
- nuget OpenTelemetry.Exporter.OpenTelemetryProtocol 1.15.3
- opentelemetry opentelemetry.api 1.15.2
- opentelemetry opentelemetry.extensions.propagators 1.15.2
- opentelemetry opentelemetry 1.15.2
- github.com/open-telemetry/opentelemetry-dotnet#5980 pull request
- github.com/open-telemetry/opentelemetry-dotnet#7064 pull request
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 6 mo ago
Exploit prediction
0.19% chance of exploitation in the next 30 days, higher than 8% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.3 | CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H |
| GitHub | 3.1 | 5.3 | CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVD | 3.1 | 5.3 | CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| nuget | OpenTelemetry.Exporter.OpenTelemetryProtocol | >=1.13.1, <1.15.3 |
1.15.3 |
Affected products
- open-telemetry opentelemetry-dotnet
- open-telemetry OpenTelemetry.Exporter.OpenTelemetryProtocol
Classification
- Weakness
-
- CWE-789 Memory Allocation with Excessive Size Value
References
-
github.com
/open-telemetry/opentelemetry-dotnet/pull/5980
web, issue-tracking, patch
-
github.com
/open-telemetry/opentelemetry-dotnet/pull/7064
web, issue-tracking, patch
-
github.com
/open-telemetry/opentelemetry-dotnet/security/advisories/GHSA-mr8r-92fq-pj8p
web, mitigation, vendor-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2026-40891
advisory
-
github.com
/open-telemetry/opentelemetry-dotnet
package
Sources
- CVE List CVE-2026-40891
- GitHub Advisory GHSA-mr8r-92fq-pj8p
- NVD CVE-2026-40891
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.